And then, there is wave power, which is essentially wind energy decoupled from its origin in time and space, has(had) extremely encouraging working prototypes, like the Pelamis design:

https://www.youtube.com/watch?v=l3-SXFtPYe0

This was a [prototype 750 kW (KiloWatt) plant operating at Orkney Islands and near Portugal](https://en.wikipedia.org/wiki/Pelamis_Wave_Energy_Converter) - as a reference, it took wind power plants more than 20 years of enthusiastic development until the installed power reached 500 kW.

It is a shame that this development was shut down (while the design has been reported to be picked up by, guess whom, the Chinese), while being owned by E.ON. But I am sure more developments will follow, as the design is an excellent idea.